Possessed ][+ Mainboard

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Possessed ][+ Mainboard

Here's an anecdote to take to the bank. I have a Rev D ][+ board that was previously damaged and malfunctioned. A while back, I restored it, tested it, did a full burn in, RAM tests, the lot, and it passed them all. I put it into a static bag and put it on a shelf. 

 

Today, when I was putting a board in a system, I selected that one first, as I had marked it 'Restored, 100%, 48K'. After I completely installed the board, I powered it up, and.... Screen of rubbish characters. Might be the 9334, but my point in all of this, is that I did not first bench test it again ere installing it. IDK what would have gone bad in two months sitting on a shelf, but I marked the bag 100% burn in verified--and this board had some suspect issues originally where it had phantom problems that some standard chip swaps seemed to cure. 

 

The takeaway, is even if you tested something two months earlier, test it again ere spending the time installing it. 

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Shelf time is cruel sometimes

Shelf time is cruel sometimes.

I've run into that situation more than once.  I suspect that it miche be socket or cold-solder joint related.  Or maybe a flakey 9334, who knows?

 

I've got a Microsoft 16K card that doesn't work at all when it's cold. The computer doesn't even recognize that it's there.

Within a minute it's recognized but fails.  Over the next minute or so RAM tests performed show fewer and fewer errors until the errors disappear.

Once it's allowed to warm up for evan 3 minutes it works perfectly and passes every single test I can throw at it.

 

I've been chasing that one for weeks, but since I can only test it when it's stone cold my testing windows are extremely short.

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Sounds like internal IC breakdown

Sounds like internal IC breakdown such as the lead weld to the actual silicone internal to the IC has given up the ghost.  Likely makes connection with thermal expansion.  My guess anyway.

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macnoyd wrote:Sounds like
macnoyd wrote:

Sounds like internal IC breakdown such as the lead weld to the actual silicone internal to the IC has given up the ghost.  Likely makes connection with thermal expansion.  My guess anyway.

Very probably an issue that dissipates with heat. Pretty sure that this is what you are pointing toward, and it may likely be this. It's just annoying. 

 

I suppose, that if I solve this, I might post about it, but it isn't high up on my prior5ity list. I more or less simply wanted to share my little anecdote and move on. I have three ][/][+ boards not in cases: One I know is fine, the second (the board in question), I thought was fine, and the third is a misfit Rev 4 board that needs a lot of reworking. I spent one good working board to make me Beltron functional, until I can diagnose and repair the Beltron mainboard, if that ever occurs. 

 

I need one for a B&H, but I expect this to be the story of these boards. Every system that I have had, maintained, or worked on since it was new never had any issues and works as new to this day. Everything that I receive as trade or buy 'as-is' is horribly broken. 

 

This isn't some sort of 'help me' topic. It is more or less me venting about stupid things, such as not triple-checking the working status of a board ere spending an hour installing it. If I had more members on the Apple 77 Discord server, I would have posted it there, but people (for whatever reason) join that, then leave b/c there isn't activity; b ut the only way to generate activity is for people to sign up and post. I suppose that it doesn't appeal as much as forums, and that part, I understand. 

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